The vacuum removal of particles, particularly of fine size, commonly entails materials such as gypsum, encountered with sanding of wallboard; sawdust; house dust and the like. Continued efficacious removal of the fine particles further requires the utilization of replaceable filtration elements usually made of cloth, foam, paper and the like which trap the particles. However such filtration elements must be periodically replaced since clogging reduces vacuum removal efficiency and this is at an economic cost and with lost time involved in the replacement. In addition, such replacements are at periodic short time intervals, especially with heavy duty and continuous applications.
In response to the demands placed on solid porous filters, fluid filtration has been utilized wherein the particle laden air is vacuum drawn into contact with a fluid (invariably water) surface with particles being removed by such water surface as a filtration of the air. Efficiency of such removal is however less than ideal since the air is not actually drawn through the water in a manner similar to the solid filters, but is instead caused to contact the surface of the water, and at most only bubbled through a short depth beneath the exposed surface.